88 BACTERIA IN DAILY LIFE 



ous manner not yet understood, far from benefit- 

 ing the animal and assisting it in combating 

 these diseases, actually contributing to the lethal 

 action of these bacteria. It has been asserted 

 on the authority of some medical men that in 

 cases of small-pox recovery is rendered more easy 

 and rapid when light is excluded from the 

 patient's room ; whether Dr. Masella's experi- 

 ments will permit of any such interpretation 

 being placed upon them remains to be seen ; 

 they are, at any rate, extremely suggestive. 



That it is possible for temperature to have 

 some determining influence upon the course of 

 certain diseases has been shown by O. Voges, 

 who, experimenting with a minute bacillus which 

 he isolated from tumours characteristic of a 

 cattle disease very prevalent in South America, 

 found that although this bacillus was the un- 

 doubted fons et origo of the disease, he could 

 not produce fatal results in animals if he kept 

 them in cold surroundings ; only when the tem- 

 perature was raised to from 35-45 degrees Centi- 

 grade did the infected animals succumb. The 

 dependence of the activity and virulence of this 

 micro-organism upon temperature is also borne 

 out in actual experience, the disease being the 

 more prevalent and the more fatal the hotter 

 the climate of the country. 



